How much faster are the original "Aluminum" iMac Core 2 Duo models than the previous "White" iMac Core 2 Duo models?

Please note that all models mentioned in this Q&A have been discontinued. The original "Aluminum" iMac Core 2 Duo systems were replaced by the "Early 2008/Penryn Aluminum" iMac Core 2 Duo line.

Apple did not release "official" benchmarks or real-world tests comparing the speed of the original "Aluminum" iMac Core 2 Duo models to the previous "White" iMac Core 2 Duo series.

However, review a quick comparison of the differences between the original "Aluminum" iMac Core 2 Duo models -- the iMac "Core 2 Duo" 2.0 20-Inch (Al), "Core 2 Duo" 2.4 20-Inch (Al), "Core 2 Duo" 2.4 24-Inch (Al), and "Core 2 Extreme" 2.8 24-Inch (Al) -- and the models that the line replaced and one would notice that of the "stock Aluminum" systems -- some have faster processors (the "stock Aluminum" models have 2.0 GHz and 2.4 GHz processors compared to 2.0 GHz and 2.16 GHz for their predecessors). The "Aluminum" Core 2 Duo line, however, also has a faster frontside bus (800 MHz compared to 667 MHz).

Numerous websites have benchmarked and tested the original "Aluminum" iMac Core 2 Duo systems, including MacWorld, AppleInsider, and ArsTechnica among others. All of these reviews and test results should be read in their entirety for the complete perspectives provided by each author, but a helpful clipping from each is provided below for your convenience.

In a "First Look," MacWorld reported:

Looking at the numbers, the new 2 GHz 20-inch iMac turned in an impressive performance stacked up against the marginally faster 2.16 GHz processor in the older machine. That speed advantage helped the old iMacs edge past the new 2 GHz model in some tests, but the new low-end iMac actually nosed past the older model by one point in our Speedmark suite. . .

But people deciding whether to upgrade to this iMac likely are not making the leap from the machines released a year ago; rather, they’re making the jump from older models, including PowerPC-based hardware. . . Comparing Speedmark scores, the new top of line iMac turned in a 43-percent faster Speedmark score [than the iMac G5/2.1 20-Inch (iSight) from 2005]. In some processor intensive tests, the new iMacs finished in less than half the time it took for the G5 model. The new 2 GHz iMac was 32-percent faster in Speedmark.

Conducting Cinebench, Geekbench, and XBench tests, AppleInsider discovered:

In our benchmark tests against the last 20-inch iMac G5, the new 24-inch Core 2 Duo is simply in a different class of performance. Most tests which focus on the CPU show that just one of the two 2.4 GHz Intel cores can nearly double the speed of the 2.1 GHz PowerPC chip; in tests aware of multiple cores, the newest Core 2 Duo is well over three times faster. Cinebench was especially impressive and saw 3D models render in just a third of the time.

In an extensive battery of tests including synthetic benchmarks and measurement of real world performance, ArsTechnica compared the new iMac "Core 2 Duo" 2.4 20-Inch (Al) to the iMac "Core Duo" 1.83 17-Inch, MacBook Pro "Core 2 Duo" 2.4 17" (SR), and Mac Pro "Quad Core" 2.66 and found that:

In terms of performance, the iMac acquits itself very well. For the most part, it outdid a MacBook Pro with an identical CPU and FSB in my testing, and it was more than competitive with a Mac Pro. The benchmark results also indicate how much of a difference the FSB can make, as the older Core Duo iMac received a beatdown that wasn't indicative of the 570 MHz difference in clock speed.

Ultimately, the speed gain of the "Aluminum" iMac Core 2 Duo models compared to their immediate predecessors is decidedly modest but more substantial compared to older models, as one would generally expect.

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